Adsorption and Aggregation Properties of a Series of Semifluorinated, Unsaturated Fatty Acid Esters from Nonaqueous Solution

A Series of unsaturated, fattty acid esters of perfluorooctylethyl alcohol have been prepared. Surface tension isotherms and aggregation behavior were measured in n-butyl acetate solution. Analysis of the surface tension data using a Frumkin equation of state yielded thermodynamic parameters for adsorption. Degree of unsaturation or stereochemistry did not have much effect on the free energy of adsorption. These fluorinated esters were to form small ( [similar to] 2 - 6) aggregates beginning at concentrations > [similar to] 10-2 mol/L. A mass action analysis of the aggregation data was used to determine free energies of micellization. Degree of unsaturation and stereochemistry had a minor effect on aggregation thermodynamics and aggregate size.